Maclean Road poll workers said there were no Republican ballots or GOP volunteers when the location first opened. Thompson and his wife stepped in to help Republican voters so that no one would be turned away.

"We've got some really good training. We're trained to do this," Thompson said.

Election workers rushed a stack of Republican ballots to the precinct from an office downtown.

Problems were also reported at the Battlefield Park polling location.

"We were at another poll site on Ellis Avenue, and then nobody showed up here, so we were told to come (to Battlefield Park)," poll worker Brittany Johnson said.

Everything was in place at that polling location in time for the doors to open.

"All the parties rely basically on volunteers to show up," Hinds County Republican Party secretary Amile Wilson said.

Each party assigns hundreds of volunteers to work the polls. Wilson said it's just too many.

"It becomes a real struggle trying to find that many people every time we have an election," Wilson said.

Poll workers said no one at either location was turned away without voting.

Polls are open until 7 p.m., and voters must have a driver's license or another form of government-issued photo identification to vote.

Because ballots were set weeks ago, they still contain names of candidates who have dropped out of the race for the White House.

Republicans Donald Trump and Ted Cruz campaigned in Mississippi on Monday, and John Kasich was in the state last week. Marco Rubio hasn't personally campaigned in the state, but like other candidates, he's promoting local endorsements.

Democrats Hillary Clinton and Bernie Sanders concentrated on Michigan, which also has primaries Tuesday. Former President Bill Clinton campaigned for his wife last week in Jackson.